Communication control device, communication control method, communication system and communication device

ABSTRACT

Provided is a communication control device controlling communication of multiple secondary usage nodes providing second communication services using a part of a frequency band assigned to a first communication service, including a communication unit receiving service area information for estimating service areas of the second communication services provided by the secondary usage nodes and access technique information indicating radio access techniques usable by the secondary usage nodes, a storage unit storing information on the service area and access technique received by the communication unit, an estimation unit estimating service areas of multiple second communication services, and a control unit notifying a secondary usage node providing one of the multiple second communication services of a radio access technique or a channel recommended to the at least one second communication service on the basis of a location relationship between the service areas estimated by the estimation unit and the access technique information.

TECHNICAL FIELD

The present invention relates to a communication control device, acommunication control method, a communication system and a communicationdevice.

BACKGROUND ART

Recently, discussions for enabling a primarily used frequency band(spectrum) to be used in a second communication service according to theuse condition of the frequency band have been in progress. For example,a standard specification for allowing an unused channel (TV white space)included in the frequency band of US digital TV broadcasting to beavailable for radio communication is under examination in IEEE802.22working group (see Non-Patent Literature 1 below).

According to a recommendation of the Federal Communications Commission(FCC) on November 2003, the discussions have been directed towardpermitting secondary usage of the TV white space by using acommunication device that fulfills a predetermined condition and hasreceived an authentication. This recommendation of FCC accepts thestandard specification of IEEE802.22, which is the first standardizationof secondary usage of the TV white space, and also covers the activitiesof a new study group in IEEE. Technically, since it is necessary toperform signal detection at a level of −114 [dBm] (SNR is about −19 [dB]when Noise Figure (NF) is 11 [dB], for example) using existingtechnology for example, an auxiliary function such as Geo-locationDatabase Access is expected to be necessary (see Non-Patent Literature 2below). Also, FCC is under examination for opening a 250-MHz band, whichis a part of a 5-GHz band, as a new channel for secondary usage.

Furthermore, in the EU, there are moves afoot to universally allocate adedicated control channel referred to as Cognitive Pilot Channel (CPC)for implementing Dynamic Spectrum Access (DSA) under a long-termstrategy. Allocation of CPC has been incorporated in the agenda ofInternational Telecommunication Union (ITU)-WP11 in 2011. Technologicalstudies for a secondary usage system that performs DSA are also underway in the IEEE Standards Coordinating Committee (SCC) 41.

In general, when a frequency band assigned to a communication servicerelated to primary usage (will be referred to as a first communicationservice below) is secondarily used, it is important that a communicationservice related to secondary usage. (will be referred to as a secondcommunication service below) not interfere with the first communicationservice. For this reason, Non-Patent Literature 2 below recommendsinstallation of a data server that receives administrator information,location information, and the like from a secondary usage node whichwill provide a second communication service and accumulates these piecesof information in a database. In this case, the data server specifies achannel that can be provided for secondary usage according to a requestfrom the secondary usage node, and notifies the secondary usage node ofthe specified channel. When the secondary usage node uses the channelnotified in this way by the data server, interference with a firstcommunication service is prevented.

CITATION LIST Non-Patent Literature

Non-Patent Literature 1: “IEEE802.22 WG on WRANs,” [online], [searchedJul. 1, 2010], Internet <URL:http://www.ieee802.org/22/>

Non-Patent Literature 2: “SECOND REPORT AND ORDER AND MEMORANDUM OPINIONAND ORDER,” [online], [searched Jul. 1, 2010], Internet <URL:http:/hraunfoss.fcc.gov/edocs_public/attachmatch/FCC-08-260A1.pdf>

SUMMARY OF INVENTION Technical Problem

However, when only the aforementioned information provided by the dataserver is used, there are a plurality of secondary usage nodes, andthere is still a risk that a problem such as interference, signalcollision, or the like between second communication services will occurin a situation in which the plurality of second communication servicescan be provided. Also, when a plurality of second communication servicesare separately provided without cooperation with each other, it isdifficult to achieve high efficiency in frequency usage. Accordingly, itis preferable for respective second communication services to beprovided after configurations for secondary usage such as radio accesstechniques, channels, and the like are mutually adjusted.

Here, technology related to the present disclosure provides as new andimproved communication control device, communication control method,communication system, and communication device that enable an adjustmentof a configuration for secondary usage between a plurality of secondcommunication services.

Solution to Problem

According to an embodiment of the present disclosure, there is provideda communication control device which controls communication of one ormore secondary usage nodes providing second communication services usinga part of a frequency band assigned to a first communication service,the communication control device, including a communication unit thatreceives service area information for estimating service areas of thesecond communication services provided by the secondary usage nodes andaccess technique information indicating radio access techniques usableby the secondary usage nodes from the respective secondary usage nodes,a storage unit that stores the service area information and the accesstechnique information received by the communication unit, an estimationunit that estimates service areas of two or more second communicationservices using the service area information, and a control unit thatnotifies a secondary usage node providing at least one of the two ormore second communication services of a radio access technique or achannel recommended to the at least one second communication service onthe basis of a location relationship between the service areas estimatedby the estimation unit and the access technique information.

The service area information may include data about a location of asecondary usage node providing the corresponding second communicationservice, maximum transmission power applied to the secondary usage node,and an antenna height of the secondary usage node.

The communication unit may further receive permissible channelinformation indicating a channel that the secondary usage node isallowed to use from the secondary usage node, and the control unit mayselect a channel recommended to each secondary usage node from amongchannels indicated by the permissible channel information received fromthe secondary usage node.

The control unit may recommend use of the same radio access technique,when service areas of two second communication services overlap andradio access techniques usable by two secondary usage nodes respectivelyproviding the two second communication services are the same.

The control unit may cause the communication unit to transmit asynchronization signal to the two secondary usage nodes, when one of thetwo second communication nodes is not included in a service area of theother second communication service.

The control unit may recommend that a secondary usage node providing oneof the second communication services use a channel different from achannel used by the other second communication service, when serviceareas of two second communication services overlap and radio accesstechniques usable by two secondary usage nodes respectively providingthe two second communication services are different.

The control unit may recommend that two secondary usage nodesrespectively providing the two second communication services use acommon channel, when service areas of two second communication servicesdo not overlap and a level of mutual interference between the two secondcommunication services does not exceed an allowable interference level.

The control unit may notify the secondary usage node or anothersecondary usage node whose service area overlaps a service area of thesecondary usage node of a recommended radio access technique or arecommended channel, according to a request from a secondary usage nodedetecting interference between second communication services.

The control unit may notify the secondary usage node or anothersecondary usage node capable of using the same radio access technique asthe secondary usage node of a recommended radio access technique or arecommended channel, according to a request from a secondary usage noderequesting expansion of a service area.

The control unit may notify the secondary usage node of a recommendedchannel, according to a request from a secondary usage node requestingexpansion of a band.

The control unit may preferentially recommend a channel whosetransmission power has no limitation, when there are a plurality ofrecommendable channels.

Further, according to another embodiment of the present disclosure,there is provided a communication control method for controllingcommunication of one or more secondary usage nodes providing secondcommunication services using a part of a frequency band assigned to afirst communication service, the communication control method, includingreceiving service area information for estimating service areas of thesecond communication services provided by the secondary usage nodes andaccess technique information indicating radio access techniques usableby the secondary usage nodes from the respective secondary usage nodes,storing the received service area information and access techniqueinformation, estimating service areas of two or more secondcommunication services using the service area information, and notifyinga secondary usage node providing at least one of the two or more secondcommunication services of a radio access technique or a channelrecommended to the at least one second communication service on thebasis of a location relationship between the estimated service areas andthe access technique information.

Further, according to another embodiment of the present disclosure,there is provided a communication system which includes one or moresecondary usage nodes providing second communication services using apart of a frequency band assigned to a first communication service and acommunication control device controlling communication of the one ormore secondary usage nodes. The communication control device includes acommunication unit that receives service area information for estimatingservice areas of the second communication services provided by thesecondary usage nodes and access technique information indicating radioaccess techniques usable by the secondary usage nodes from therespective secondary usage nodes, a storage unit that stores the servicearea information and the access technique information received by thecommunication unit, an estimation unit that estimates service areas oftwo or more second communication services using the service areainformation, and a control unit that notifies a secondary usage nodeproviding at least one of the two or more second communication servicesof a radio access technique or a channel recommended to the at least onesecond communication service on the basis of a location relationshipbetween the service areas estimated by the estimation unit and theaccess technique information. Each of the secondary usage nodes includesa communication unit that transmits the service area information and theaccess technique information to the communication control device, and asecondary usage control unit that provides a second communicationservice to one or more terminal devices using the radio access techniqueor the channel recommended by the communication control device.

Further, according to another embodiment of the present disclosure,there is provided a communication device which provides a secondcommunication service using a part of a frequency band assigned to afirst communication service, the communication device including acommunication unit that transmits service area information forestimating a service area of the second communication service providedby the communication device and access technique information indicatinga radio access technique usable by the communication device to anotherdevice, and a secondary usage control unit that provides the secondcommunication service to one or more terminal devices using a radioaccess technique or a channel recommended by the other device on thebasis of a location relationship between a service area of the secondcommunication service estimated using the service area information and aservice area of another second communication service and the accesstechnique information.

Advantageous Effects of invention

As described above the communication control device, the communicationcontrol method, the communication system, and the communication devicerelated to the present disclosure enable an adjustment of aconfiguration for secondary usage between a plurality of secondcommunication services.

BRIEF DESCRIPTION OF DRAWINGS

[FIG. 1] FIG. 1 is an explanatory diagram illustrating an outline of acommunication system related to one embodiment.

[FIG. 2] FIG. 2 is a sequence diagram showing an example of the flow ofa process between a secondary usage node and a data server.

[FIG. 3] FIG. 3 is a block diagram showing an example of asconfiguration of a communication control device related to oneembodiment.

[FIG. 4] FIG. 4 is an explanatory diagram illustrating a first exampleof a location relationship between a second communication service and aservice area.

[FIG. 5] FIG. 5 is an explanatory diagram illustrating a second exampleof a location relationship between a second communication service and aservice area.

[FIG. 6] FIG. 6 is an explanatory diagram illustrating a third exampleof a location relationship between a second communication service and aservice area.

[FIG. 7] FIG. 7 is a block diagram showing an example of a configurationof a secondary usage node related to one embodiment.

[FIG. 8] FIG. 8 is a sequence diagram showing an example of the flow ofa communication control process between a communication control deviceand a secondary usage node related to one embodiment.

[FIG. 9] FIG. 9 is a flowchart showing an example of the flow of aservice area estimation process related to one embodiment.

[FIG. 10A] FIG. 10A is a first part of as flowchart showing an exampleof the flow of a process of determining a recommended serviceconfiguration related to one embodiment.

[FIG. 10B] FIG. 10B is a second part of the flowchart showing an exampleof the flow of the process of determining a recommended serviceconfiguration related to one embodiment.

[FIG. 10C] FIG. 10C is a third part of the flowchart showing an exampleof the flow of the process of determining a recommended serviceconfiguration related to one embodiment.

[FIG. 11A] FIG. 11A is a first explanatory diagram illustrating a firstscenario of as communication control process related to one embodiment.

[FIG. 11B] FIG. 11B is a second explanatory diagram illustrating thefirst scenario of the communication control process related to oneembodiment.

[FIG. 12A] FIG. 12A is a first explanatory diagram illustrating a secondscenario of the communication control process related to one embodiment.

[FIG. 12B] FIG. 12B is a second explanatory diagram illustrating thesecond scenario of the communication control process related to oneembodiment.

[FIG. 13A] FIG. 13A is a first explanatory diagram illustrating a thirdscenario of the communication control process related to one embodiment.

[FIG. 13B] FIG. 13B is a second explanatory diagram illustrating thethird scenario of the communication control process related to oneembodiment.

[FIG. 14A] FIG. 14A is a first explanatory diagram illustrating a fourthscenario of the communication control process related to one embodiment.

[FIG. 14B] FIG. 14B is a second explanatory diagram illustrating thefourth scenario of the communication control process related to oneembodiment.

[FIG. 15A] FIG. 15A is a first explanatory diagram illustrating a fifthscenario of the communication control process related to one embodiment.

[FIG. 15B] FIG. 15B is a second explanatory diagram illustrating thefifth scenario of the communication control process related to oneembodiment.

DESCRIPTION OF EMBODIMENTS

Hereinafter, preferred embodiments of the present invention will bedescribed in detail with reference to the appended drawings. Note that,in this specification and the drawings, elements that have substantiallythe same function and structure are denoted with the same referencesigns, and repeated explanation is omitted.

“Embodiments for Implementing Invention” will be described according tothe following sequence.

1. Outline of System

2. Example of Configuration of Device Related to One Embodiment

2-1. Example of Configuration of Communication Control Device

2-2. Example of Location Relationship Between Service Areas

2-3. Example of Configuration of Secondary Usage Node

3. Flow of Process Related to One Embodiment

3-1. Communication Control Process

3-2. Service Area Determination Process

3-3. Process of Determining Recommended Service Configuration

4. Typical Scenarios for Communication Control

4-1. First Scenario

4-2. Second Scenario

4-3. Third Scenario

4-4. Fourth Scenario

4-5. Fifth Scenario

5. Summarization

1. Outline of System

FIG. 1 is an explanatory diagram illustrating an outline of acommunication system related to one embodiment. Referring to FIG. 1, aprimary usage node 10, secondary usage nodes 20 a and 20 b, a dataserver 40, and a communication control device 100 are shown.

The primary usage node 10 is a node that transmits/receives radiosignals for a first communication service using a frequency band whichhas been assigned in advance. However, the primary usage node 10 doesnot necessarily use the assigned whole frequency band. In the example ofFIG. 1, a frequency band including channels F1, F2 and F3 has beenassigned, but the primary usage node 10 is using only the channel F1among them. The first communication service may be an arbitrarycommunication service including, for example, a digital TV broadcastingservice, a satellite communication service, a mobile communicationservice, or the like. In addition, for example, when the firstcommunication service is a mobile communication service, the primaryusage node 10 can correspond to a base station.

A boundary B01 shown in FIG. 1 is an external boundary of a service areaof the first communication service provided by the primary usage node10. A terminal device (not shown) that is located within the boundaryB01 can receive the first communication service provided by the primary'usage node 10. A boundary B02 is an external boundary of a guide areaset around the service area of the first communication service. Theguide area is a buffer area set between the service area of the firstcommunication service and a so-called white space. Since there is theguide area, even when a frequency band is secondarily used in the whitespace, a probability that a problem such as interference will occur inthe terminal device located in the service area is reduced.

Between the boundary B02 and a boundary B03, the so-called white spaceis present. In the example of FIG. 1, the secondary usage nodes 20 a and20 b are located in the white space. Each or the secondary usage nodes20 a and 20 b is a communication device that provides a secondcommunication service using a part of the frequency band assigned to thefirst communication service. In the following description of thisspecification, when there is no particular necessity to distinguish thesecondary usage nodes 20 a and 20 b from each other, letters at the endsof the symbols are omitted, and the secondary usage nodes 20 a and 20 bwill be generally referred to as secondary usage nodes 20.

A secondary usage node 20 determines whether or not secondary usage isavailable according to a predetermined spectrum policy, receives achannel provided by the data server 40, and then provides a secondcommunication service to terminal devices (not shown) located around it.Without being limited to the example of FIG. 1, the secondary usage node20 may be located in the service area of the first communication serviceor around the service area. For example, in order to cover a spectrumhole that is generated in the service area due to the influence ofshadowing (shielding), fading, or the like, a secondary usage node maybe installed in the service area of the first communication service.

The second communication service typically denotes an additional orsubstitutionary communication service that is provided using a part orthe whole of a frequency band assigned to the first communicationservice. In the meaning of the term “secondary usage,” the firstcommunication service and the second communication service may becommunication services of different types or services of the same type.Communication services of different types denote communication servicesof two or more different types that can be selected from arbitrarycommunication services, for example, a digital TV broadcasting service,a satellite communication service, a mobile communication service, awireless LAN access service, a Peer-To-Peer (P2P) connection service,and the like. On the other hand, services of the same type can include arelationship between a service based on a macro-cell provided by acommunication provider, for example, of a mobile communication service,and a service based on a femto-cell managed by a user or a MobileVirtual Network Operator (MVNO). In addition, services of the same typecan also include a relationship between a service provided by a basestation of a communication service according to WiMAX, Long TermEvolution (LTE), LTE-Advanced (LTE-A), or the like and a serviceprovided by a relay station (relay node) to cover a spectrum hole. Also,the second communication service may be a service that uses a pluralityof fragmentary frequency bands aggregated using spectrum aggregationtechnology. Furthermore, the second communication service may be asupplementary communication service that is provided by a femto-cellgroup, a relay station group, or a small or medium-sized base stationgroup, which provides a smaller service area than a base station,present within a service area of the base station. The outline of eachembodiment described in this specification is widely applicable to everytype of mode of such secondary usages.

The data server 40 has a database that receives node informationincluding administrator information, location information, and the likefrom the secondary usage node 20 and accumulates the received nodeinformation. The data server 40 can be connected with the primary usagenode 10 and the secondary usage node 20 via, for example, the Internet,a backbone network of the first communication service, or the like. Thedata server 40 accumulates the aforementioned node information receivedfrom the secondary usage node 20. Also, according to a request from thesecondary usage node 20, the data server 40 provides information, forexample, a channel that can be provided for secondary usage, maximumtransmission power, a spectrum mask, and the like to the secondary usagenode 20. In this way, the secondary usage node 20 becomes able to startthe second communication service.

FIG. 2 is a sequence diagram showing an example of the flow of a processbetween the secondary usage node 20 and the data server 40 exemplifiedin FIG. 1. Referring to FIG. 2, the secondary usage node 20 that willsecondarily use a frequency band assigned to the first communicationservice transmits node information to the data server 40 first, therebyrequesting registration of the node information (step S02). Then, thedata server 40 registers the node information received from thesecondary usage node 20 in a database (step S04).

Here, the node information registered in the database includes, forexample, the following information:

-   -   Regulation ID: an ID given when a node is authenticated as a        device that can be used for secondary usage. The regulation ID        can be included in node information in the case of secondary        usage of a TV white space.    -   Manufacturer ID: an ID of a manufacturer of the device.    -   Location Data: indicates a location of the device that is        dynamically measured using a positioning means such as GPS, or        kept stationary.    -   Antenna Height: a height of an antenna of the device. For        example, Height Above Average Terrain of the tx (HAAT) can be        used.    -   Administrator information: includes a device owner's name,        address, mail address, and the like.

Next, the data server 40 transmits an acknowledgement signal(confirmation) confirming that registration of the node information hasbeen finished to the secondary usage node 20 (step S06). Next, thesecondary usage node 20 requests permission-for secondary usage from thedata server 40 (step S08). Then, the data server 40 determines, forexample, a channel that can be provided to the secondary usage node 20(for example, an unused part of a frequency hand assigned to the firstcommunication service), and permits secondary usage to the secondaryusage node 20 when there is a providable channel (step S10). Here,channels that can be provided to the secondary usage node 20 can beclassified as restricted channels that are limited to a lowertransmission power, which can be used by the secondary usage node 20,than a general transmission power, and normal channels that are notlimited by such a limitation. When a normal channel can be provided, thedata server 40 may preferentially provide the normal channel to thesecondary usage node 20. For example, when an adjacent channel of achannel is not used by the first communication service in the case of aso-called Personal/Portable Mode-I client in an FCC standard, a maximumtransmission power of 100 m[W] is permitted. Such a channel can betreated as a common channel. Meanwhile, when an adjacent channel of achannel is used by the first communication service, a maximumtransmission power is limited to 40 m[W]. Such a channel can be treatedas a restricted channel.

In step S10, the data server 40 provides the secondary usage node 20with, for example, the following information:

-   -   Maximum Transmission Power: a maximum of transmission power at        which the secondary usage node 20 is allowed to perform        radiation.    -   Permissible Channel information: a list of channel numbers        specifying channels that can be provided to the secondary usage        node 20. The frequency hand assigned to the first communication        service can be divided into a plurality of channels in advance,        and channel numbers can be given to the respective channels.        Instead of the channel numbers, center frequencies of the        channels may be used. The permissible channel information can        also include information indicating channel-specific channel        categories (whether a channel is a normal channel or a        restricted channel, and the like).    -   Regulatory Information; can include rules for secondary usage        such as a spectrum mask.

In this specification, these pieces of information that are providedfrom the data server 40 to the secondary usage node 20 are referred toas grant information.

After these steps, the secondary usage node 20 can start secondary usageof the frequency band assigned to the first communication service.

The communication control device 100 is a communication device thatcontrols communication of one or more secondary usage nodes 20. Like thedata server 40, the communication control device 100 also can beconnected with the primary usage node 10 and the secondary usage nodes20 via, for example, the Internet, the backbone network of the firstcommunication service, or the like. The communication control device 100may be physically the same device as the database 40. As will bedescribed in detail in the next chapter, the communication controldevice 100 adjusts a configuration of radio access techniques, channels,and the like of second communication services provided by the respectivesecondary usage nodes 20 between the plurality of second communicationservices using node information about the secondary usage nodes 20,information provided by the data server 40, and the like.

2. Example of Configuration of Device Related to One Embodiment 2.1.Example of Configuration of Communication Control Device

FIG. 3 is a block diagram showing an example of a configuration of thecommunication control device 100 related to this embodiment. Referringto FIG. 3, the communication control device 100 includes a communicationunit 110, a storage unit 120, en estimation unit 130, and a control unit140.

(Communication Unit)

The communication unit 110 is a communication interface for thecommunication control device 100 to communicate with the secondary usagenodes 20. In addition, the communication unit 110 may be able tocommunicate with the data server 40. In this embodiment, thecommunication unit 110 receives a request for registration of secondaryusage from, for example, each secondary usage node 20 to which secondaryusage is permitted.

The request for registration of secondary usage includes, for example,the following information:

-   -   Regulation ID: information that can be registered as node        information in a data server.    -   Manufacturer ID: information that can be registered as node        information in a data server.    -   Location Data: information that can be registered as node        information in a data server.    -   Antenna Height: information that can be registered as node        information in a data server.    -   Maximum Transmission Power: information that can be provided as        grant information from a data server.    -   Permissible Channel Information: information that can be        provided as grant information from a data server.    -   Regulatory Information: information that can be provided as        grant information from a data server.    -   Utilization Channel Information: a number of a channel that a        secondary usage node will use for a second communication service        among channels included in a list of permissible channel        information.    -   Access Technique Information: a list of access technique numbers        indicating radio access techniques that can be used (and are        currently in use) by a secondary usage node. The numbers can be        given in advance according to each radio access technique such        as IEEE802.11af, 11g or 11n, IEEE802.22, IEEE802.16, LTD, LTE-A,        or the like. Instead of a list of access technique numbers, the        access technique information may include a bit string, a code        value, or the like that indicates whether or not respective        radio access techniques are supported. Also, the access        technique information may include information indicating whether        or not a protocol for coexistence of communication services,        which will be described later, can be used.

In this embodiment, the communication control device 100 handles thelocation data, the antenna height, and the maximum transmission poweramong these pieces of information as service area information forestimating a service area of a second communication service provided bythe secondary usage node 20. The information mentioned here is merely anexample. In other words, the request for registration of secondary usagethat is transmitted from the secondary usage node 20 to thecommunication control device 100 may not include a part of theaforementioned information, or may further include additionalinformation. Also, the communication control device 100 may acquire apart of the aforementioned information not from the secondary usage node20 but from the data server 40.

The communication unit 110 stores information received from eachsecondary usage node 20 in the storage unit 120. Also, the communicationunit 110 receives an adjustment request from a secondary usage node 20that requests an adjustment between second communication services. Theadjustment request from the secondary usage node 20 is processed by thecontrol unit 140 which will be described later.

(Storage Unit)

The storage unit 120 is implemented using a storage medium, for example,a hard disc, a semiconductor memory, or the like. In this embodiment,the storage unit 120 stores information included in the registrationrequest that is received by the communication unit 110. Among theinformation stored in the storage unit 120, the service area informationincluding the location data, the antenna height, and the maximumtransmission power of the secondary usage node 20 can be used by theestimation unit 130, which will be described later, to estimate aservice area. Also, the permissible channel information, the utilizationchannel information, and the access technique information can be usedfor an adjustment between second communication services by the controlunit 140 which will be described later.

(Estimation Unit)

The estimation unit 130 estimates a service area of the secondcommunication service provided by the secondary usage node 20 using theservice area information stored by the storage unit 120, that is, thelocation data, the antenna height, and the maximum transmission power ofthe secondary usage node 20. For example, the estimation unit 130approximates that the service area of the second service provided by thesecondary usage node 20 is a circular area centered on the location ofthe secondary usage node 20.

As methods for estimating a radius of a service area, two methods areconsidered. A first method is a method that is disclosed in “Method forpoint-to-area predictions for terrestrial services in the frequencyrange 30 mhz to 3000 mhz” (International Telecommunications Commission(ITU), RECOMMENDATION ITU-R P1546-3, 2007) and uses a propagation pathcurve. In this case, a statistical curve (propagation path curve) thatis based on an actual measurement value for deriving a communicationdistance (a distance at which communication is enabled with apredetermined location rate and a predetermined time rate) from anantenna height and electric field intensity is stored in advance by thestorage unit 120. The estimation unit 130 converts the maximumtransmission power of the secondary usage node 20 into electric fieldintensity, and acquires a communication distance corresponding to theantenna height and electric field intensity of the secondary usage node20 from the propagation path curve stored in the storage unit 120. Thiscommunication distance becomes a radius of the service area of thesecond communication service provided by the secondary usage node 20.

A second method for estimating a radius of a service area is a methodemploying an evaluation formula in the urban model of Okumura-Hata curve(see “Digital Wireless Transmission Technology” (written by SeiiehiSampei, Pearson Education Japan. pp.16-19)). In this case, theestimation unit 130 calculates a maximum allowable path loss from themaximum transmission power of the secondary usage node 20 and a minimumreception sensitivity of a receiver. Then, the estimation unit 130substitutes the calculated path loss and the antenna height in theevaluation formula, thereby calculating a communication distance. Thiscommunication distance becomes a radius of the service area of thesecond communication service provided by the secondary usage node 20.

The estimation unit 130 causes the storage unit 120 to store a valuethat is estimated in this way and indicates a service area of a secondcommunication service of each secondary usage node 20 (for example, acenter position and a radius of a circle).

(Control Unit)

The control unit 140 adjusts a configuration for secondary usage betweensecond communication services on the basis of a location relationshipbetween service areas estimated by the estimation unit 130 and a radioaccess technique that can be used by the secondary usage nodes 20. Theadjustment of a configuration for secondary usage between secondcommunication services includes a recommendation about a radio accesstechnique or a recommendation about a channel to be used for at leastone secondary usage node 20 in terms of for example, increase insecondary usage opportunities, improvement in frequency use efficiency,or the like. In other words, the control unit 140 determines a radioaccess technique or a channel that is recommended to at least onesecondary usage node 20 on the basis of a location relationship betweenservice areas estimated by the estimation unit 130 and a radio accesstechnique that can be used by the secondary usage nodes 20. Then, thecontrol unit 140 notifies the secondary usage nodes 20 of the determinedradio access technique or channel through the communication unit 110.According to the notification, the secondary usage node 20 performssecondary usage using the recommended new radio access technique orchannel.

2-2. Example of Location Relationship Between Service Areas

Location relationships between service areas based on which the controlunit 140 makes an adjustment between second communication services areclassified into, for example, three classes (referred to as class A,class B, and class C) exemplified in FIG. 4 to FIG. 6.

(Class A)

Referring to FIG. 4, an example of a location relationship betweenservice areas that belongs to class A is shown. In FIG. 4, a servicearea A11 of the secondary usage node 20 a and a service area A12 of thesecondary usage node 20 b overlap. In addition, the secondary usage node20 b is included in the service area A11 of the secondary usage node 20a. Likewise, the secondary usage node 20 a is included in the servicearea A12 of the secondary usage node 20 b. In such a locationrelationship, radio waves transmitted by these adjacent secondary usagenodes 20 a and 20 b become mutual interference factors, and there is aprobability that a problem will occur in secondary usage. In addition, acase in which only one of the two secondary usage nodes 20 is includedin a service area of the other may be included in class A.

For example, when service areas of two second communication serviceshave the location relationship of class A, the control unit 140 furtherdetermines whether or not there is a common radio access technique thatcan be used by the two secondary usage nodes 20 a and 20 b which providethe two second communication services respectively. For example, whenthe secondary usage node 20 a can use radio access techniques R1 and R2,and the secondary usage node 20 b can use the radio access technique R1,the radio access technique R1 is determined as a common radio accesstechnique. When there is a common radio access technique as mentionedabove, the control unit 140 recommends that the secondary usage nodes 20a and 20 b use the common radio access technique and a common channel.In this way, for example, the communication services are caused tocoexist, or a mesh network is formed between the secondary usage nodes20 a and 20 b, so that the second communication services can be managedwithout interfering with each other. For example, 11s in the IEEE802.22,Ecma392, and IEEE802.11 families, 16j in the IEEE802.16 (WiMax) family,and the like support a mesh protocol or a protocol for exchangingscheduling information. Accordingly, communication services can coexistbetween communication services that employ these radio accesstechniques. There is a case in which the IEEE802.11 family supports afunction for acquiring resource usage information about an adjacentnetwork through an access point or a terminal in a method such as beaconrequest using a public action frame, and the like. In this case also,communication services can coexist in the same way. Even if usable radioaccess techniques are different (not the same), when a combination ofthe radio access techniques is a combination of which the radio accesstechniques can coexist, the control unit 140 can cause two communicationservices to coexist in a common channel. This is the same for the otherclasses that will be described below. When usable radio accesstechniques are different from each other and are not able to coexist,the control unit 140 recommends that the secondary usage node 20 a or 20b, which provides one second communication service, use a second channelthat is different from a first channel used by the other secondcommunication service. At this time, it is more preferable that thesecond channel not be adjacent to the first channel on the frequencyaxis because interference by out-of-band radiation is also prevented. Inthis way, it is possible to separately manage the second communicationservice of the secondary usage node 20 a and the second communicationservice of the secondary usage node 20 b without them interfering witheach other.

(Class B)

Referring, to FIG. 5, an example of a location relationship betweenservice areas that belongs to class B is shown. In FIG. 5, the servicearea A11 of the secondary usage node 20 a and the service area A12 ofthe secondary usage node 20 b overlap. However, the secondary usage node20 b is not included in the service area A11 of the secondary usage node20 a, and the secondary usage node 20 a is not included in the servicearea A12 of the secondary usage node 20 b. In such a locationrelationship, radio waves interfere with a terminal device 22 a locatedin the overlapping area, and there is a probability that a partialproblem will occur in secondary usage.

For example, when service areas of two second communication serviceshave the location relationship of class B, the control unit 140 furtherdetermines whether or not there is a common radio access technique thatcan be used by the two secondary usage nodes 20 a and 20 b which providethe two second communication services respectively. When there is acommon usable radio access technique, the control unit 140 recommendsthat the secondary usage nodes 20 a and 20 b use the common radio accesstechnique and a common channel. In this way, like in the case of classA, it is possible to manage the second communication services withoutthem interfering with each other. However, in the case of class B, thesecondary usage nodes 20 a and 20 b are not able to directly receivesignals transmitted by the counterparts. For this reason, in this case,the control unit 140 causes the communication unit 110 to transmit asynchronization signal to the two secondary usage nodes 20 a and 20 b,thereby supporting coexistence of the communication services orformation of a mesh network. Like in the case of class A, when usableradio access techniques are different and are not able to coexist, thecontrol unit 140 recommends that the secondary usage node 20 a or 20 b,which provides one second communication service, use a channel(suitably, non-adjacent channel) that is different from a channel usedby the other second communication service.

(Class C)

Referring to FIG. 6, an example of a location relationship betweenservice areas that belongs to class C is shown. In FIG. 6, the servicearea A11 of the secondary usage node 20 a and the service area A12 ofthe secondary usage node 20 b do not overlap. In such a locationrelationship, the control unit 140 recommends, for example, that the twosecondary usage nodes 20 a and 20 b, which provide two secondcommunication services respectively, use a common channel irrespectiveof usable radio access techniques. In this way, it is possible toincrease a selection of channels for a secondary usage node 20 thatprovides another second communication service (not shown). However, inclass C also, when mutual interference between nodes of two secondcommunication services (for example, interference between nodes locatedin external boundary portions of two service areas) exceeds an allowablelevel, the control unit 140 may perform control for shiningcommunication resources, like in class A and class B described above.

In addition, the control unit 140 selects, for example, a channel to berecommended to each secondary usage node 20 from among channelsindicated by permissible channel information received from the secondaryusage node 20. This means that an adjustment between secondcommunication services by the communication control device 100 can beperformed within the range of regulation for secondary usage (legalregulation of each country, regulation determined between serviceproviders, or the like). Accordingly, even when the secondary usage node20 receives a notification from the communication control device 100 andchanges a channel, there is no risk of interfering with the firstcommunication service or other communication services that can bemanaged around the secondary usage node 20.

2-3. Example of Configuration of Secondary Usage Node

FIG. 7 is a block diagram showing an example of a configuration of thesecondary usage node 20 related to this embodiment. The secondary usagenode 20 may be a communication device that provides an arbitrary secondcommunication service, for example, a small or medium-sized basestation, a wireless relay station, a radio access point, or the like.Thus, there is a probability that the secondary usage node 20 will havea variety of components according to its role. However, in FIG. 7, onlycomponents that are directly related to this embodiment are shown.Referring to FIG. 7, the secondary usage node 20 includes a firstcommunication unit 210, a second communication unit 220, a storage unit230, and a secondary usage control unit 240.

(First Communication Unit)

The first communication unit 210 is a communication interface for thesecondary usage node 20 to communicate with the data server 40 and thecommunication control device 100. For example, according to control ofthe secondary usage control unit 240, the first communication unit 210transmits a request for registration of the node information, which hasbeen described with reference to FIG. 2, to the data server 40 andreceives a registration acknowledgement of the node information. Also,for example, according to control of the secondary usage control unit240, the first communication unit 210 transmits a request for secondaryusage permission to the data server 40 and receives grant informationincluding a response from the data server 40. Further, the firstcommunication unit 210 transmits a request for an adjustment betweensecond communication services, which will be described in detail later,to the communication control device 100, and receives information abouta recommended service configuration that is transmitted as a result ofthe adjustment from the communication control device 100.

(Second Communication Unit)

The second communication unit 220 is a communication interface for thesecondary usage node 20 to provide a second communication service toterminal devices around it. A radio access technique supported by thesecond communication unit 220 may be an arbitrary method such asIEEE802.11af, 11g or 11n, IEEE802.22, LTE, LTE-A, or the like. Accesstechnique information that indicates the radio access techniquesupported by the second communication unit 220 is stored in advance inthe storage unit 230.

(Storage Unit)

The storage unit 230 is implemented using a storage medium, for example,a hard disc, a semiconductor memory, or the like. In this embodiment,the storage unit 230 stores in advance the aforementioned nodeinformation that the secondary usage node 20 registers in the dataserver 40. Also, the storage unit 230 stores the aforementioned accesstechnique information in advance. When the aforementioned grantinformation is provided from the data server 40, the storage unit 230stores the grant information. Further, the secondary usage node 20stores, as utilization channel information, a number of a channel thatthe secondary usage control unit 240 will use for the secondcommunication service.

(Secondary Usage Control Unit)

The secondary usage control unit 240 controls a series of processes forsecondary usage of a frequency band by the secondary usage node 20. Forexample, the secondary usage control unit 240 performs a process withthe data server 40 exemplified in FIG. 2 through the first communicationunit 210. Also, the secondary usage control unit 240 determines thenecessity for an adjustment between second communication services, andtransmits an adjustment request to the communication control device 100when the adjustment is necessary. The case in which the adjustmentbetween second communication services is necessary can include, forexample, a case in which secondary usage is started according topermission from the data server 40, but it is not possible to obtaincommunication quality as expected due to interference between the secondcommunication services. The case in which the adjustment between secondcommunication services is necessary can also include, for example, acase in which it is preferable to expand a service area in order tocause a non-connected terminal device to participate in a secondcommunication service. The case in which the adjustment between secondcommunication services is necessary can further include, for example, acase in which it is preferable to extend a band by adding a channel. Anexample of a process after the secondary usage control unit 240transmits the adjustment request will be described in detail in the nextchapter. Without receiving the adjustment request from the secondaryusage node 20, the communication control device 100 may voluntarily makethe adjustment between the second communication services in order toimprove efficiency in frequency usage.

3. Flow of Process Related to One Embodiment

Next, with reference to FIG. 8 to FIG. 10C, description will be maderegarding the flow of a communication control process between thecommunication control device 100 and the plurality of secondary usagenodes 20 related to this embodiment.

3-1. Communication Control Process

FIG. 8 is a sequence diagram showing an example of the flow of acommunication control process between the communication control device100 and the secondary usage nodes 20 a and 20 b related to thisembodiment. It is assumed that node information has been registered inthe data server 40 by the secondary usage nodes 20 a and 20 b before theprocess of FIG. 8, and permission for secondary usage has already beengiven to the secondary usage nodes 20 a and 20 b.

Referring to FIG. 8, first, the secondary usage node 20 b requests thecommunication control device 100 to register secondary usage (stepS102). As mentioned above, a registration request transmitted from thesecondary usage node 20 b includes service area information forestimating a service area of a second communication service provided bythe secondary usage node 20 b, access technique information, and thelike. Then, the communication control device 100 stores the informationreceived from the secondary usage node 20 b in the storage unit 120(step S104). The communication control device 100 transmits anacknowledgement signal (confirmation) confirming that the registrationhas been finished to the secondary usage node 20 b (step S106).

The secondary usage node 20 a requests registration of secondary usagefrom the communication control device 100 (step S108). The registrationrequest transmitted from the secondary usage node 20 a likewise includesservice area information, access technique information, and the like.Then, the communication control device 100 stores the informationreceived from the secondary usage node 20 a in the storage unit 120(step S110). The communication control device 100 transmits anacknowledgement signal (confirmation) confirming that the registrationhas been finished to the secondary usage node 20 a (step S112).

Subsequently, the estimation unit 130 of the communication controldevice 100 estimates service areas of respective second communicationservices using the service area information that has been received fromthe respective secondary usage nodes 20 a and 20 b (step S114). Here,the service area estimation process by the estimation unit 130 may beperformed after there is a request for an adjustment between the secondcommunication services in step S116.

Next, when the necessity for an adjustment between the secondcommunication services is recognized, the secondary usage node 20 arequests the adjustment between the second communication services fromthe communication control device 100 (step S116). Here, the secondaryusage node may not request the adjustment between the secondcommunication services from the communication control device 100, butrather, the communication control device 100 may voluntarily start theadjustment between the second communication services. Subsequently, thecommunication control device 100 determines a configuration of thesecond communication services to be recommended to the secondary usagenode 20 a or another secondary usage node 20 (step S118). In the exampleof FIG. 8, the other secondary usage node 20 corresponds to thesecondary usage node 20 b. The communication control device 100 notifiesat least one of the secondary usage node 20 a and the secondary usagenode 20 b of the recommended service configuration (that is, a radioaccess technique to be used, a channel to be used, or the like) (stepS120).

3-2. Service Area Determination Process

FIG. 9 is a flowchart showing an example of the flow of a service areaestimation process by the communication control device 100 in step S114of FIG. 8.

Referring to FIG. 9, first, the estimation unit 130 of the communicationcontrol device 100 acquires a location, a maximum transmission power,and an antenna height of the secondary usage node 20 stored in thestorage unit 120 (step S132). Next, the estimation unit 130 calculates aradius of a service area of a second communication service using themaximum transmission power and the antenna height of the secondary usagenode 20 (step S134). The estimation unit 130 estimates that a circulararea which has the radius calculated in step S134 centered on thelocation of the secondary usage node 20 is the service area of thesecond communication service provided by the secondary usage node 20(step S136). When it is possible, to acquire additional information, forexample, data about the antenna directivity of the secondary usage node20, data of the surrounding terrain, or the like, the estimation unit130 may estimate a service area in an oval shape or a more complex shapeaccording to terrain, rather than a circular shape.

3-3. Process of Determining Recommended Service Configuration

FIG. 10A to FIG. 10C are flowcharts showing an example of the flow of aprocess of determining a recommended service configuration by thecommunication control device 100 in step S118 of FIG. 8.

Referring to FIG. 10A, first, the control unit 140 of the communicationcontrol device 100 determines whether or not the service areas of thetwo second communication services provided by the secondary usage nodes20 a and 20 b overlap (step S151). Whether or not the service areasoverlap may be determined on the basis of, for example, whether or notthe sum of radii of the two service areas is less than the distancebetween the secondary usage nodes 20 a and 20 b. Here, when it isdetermined that the service areas do not overlap, the process proceedsto step S170 of FIG. 10C. On the other hand, when it is determined thatthe service areas overlap, the process proceeds to step S152.

When the process proceeds to step S152, a location relationship betweenthe service areas of the two second communication services belongs toany one of class A and class B shown in FIG. 4 and FIG. 5. In this case,the control unit 140 determines whether or not there is a common radioaccess technique that can be used by the two secondary usage nodes 20 aand 20 b (step S152). Here, when it is determined that there is nocommon usable radio access technique, the process proceeds to step S161of FIG. 10B. On the other hand, when it is determined that there is acommon usable radio access technique, the process proceeds to step S153.

In step S153, the control unit 140 determines whether or not a triggerfor the ongoing process of determining a recommended serviceconfiguration is a secondary usage node (step S153). For example, whenthe communication control device 100 has received a request for anadjustment between second communication services from the secondaryusage node 20 a and thus the process of determining a recommendedservice configuration has been started, it is determined that thetrigger for the process of determining a recommended serviceconfiguration is a secondary usage node. In this case, the processproceeds to step S161 of FIG. 10B. On the other hand, when thecommunication control device 100 has actively started the process ofdetermining a recommended service configuration, the trigger for theprocess is not a secondary usage node, and thus the process proceeds tostep S154.

In step S154, the control unit 140 determines whether or not radioaccess techniques that are currently being used by the two secondaryusage nodes 20 a and 20 b are the same (step S154). Here, when it isdetermined that the radio access techniques that are currently beingused are the same, the process proceeds to step S161 of FIG. 10B. On theother hand, when it is determined that the radio access techniques thatare currently being used are not the same, the process proceeds to stepS155.

In step S155, the control unit 140 determines whether or not the commonradio access techniques that are currently being used by the twosecondary usage nodes 20 a and 20 b operate validly (that is, inparallel without causing a problem) (step S155). For example, when radioaccess techniques in which it is difficult to manage two systems inparallel are used in the situation in which the service areas overlap,the control unit 140 can determine that the common radio accesstechniques do not validly operate. In this case, the process proceeds tostep S173 of FIG. 10C. On the other hand, when it is determined that thecommon radio access techniques validly operate, the process proceeds tostep S156.

When the process proceeds to step S156, the control unit 140 recommendsthat the two secondary usage nodes 20 a and 20 b use the common usableradio access techniques and a common channel (step S156). Here, whenthere are a normal channel whose transmission power has no limitationand a restricted channel whose transmission power has a limitation asrecommendable channels, the control unit 140 may preferentiallyrecommend use of the normal channel. Also, the control unit 140determines whether or not it is necessary to supply a synchronizationsignal to the two secondary usage nodes 20 a and 20 b (step S157). Forexample, when one secondary usage node 20 is not included in a servicearea of the other secondary usage node 20, the location relationshipbetween the service areas of the two second communication servicescorresponds to class B. In this case, when it is not possible to use amesh protocol stack, for example, Ecma392 and the like, it is necessaryto assist with synchronization between the communication services. Inthe case of class A and the like also, when clock deviation is largelike in the IEEE802.11 family, it is preferable to assist withsynchronization between the communication services. In such a situation,the control unit 140 can determine that it is necessary to supply asynchronization signal to the two secondary usage nodes 20 a and 20 b.

When it is determined in step S157 that it is necessary to supply asynchronization signal, the control unit 140 supplies a synchronizationsignal to the two secondary usage nodes 20 a and 20 b through thecommunication unit 110 (step S158). On the other hand, when it isdetermined in step S157 that it is unnecessary to supply asynchronization signal, the communication control device 100 does notsupply a synchronization signal to these nodes.

In step S161 of FIG. 10B, the control unit 140 determines whether or notthere is a combination of radio access techniques that can be used bythe two secondary usage nodes 20 a and 20 b and can also coexist witheach other on a common channel in an overlapping service area (stepS161). For example, in a frame format of the standard specification ofIEEE802.22, a “Coexistence Beacon Period” for exchanging informationbetween a plurality of communication services is installed. Thesecondary usage nodes 20 a and 20 b form a mesh network by exchangingscheduling information, path information, or the like using, forexample, the “Coexistence Beacon Period,” or exchange controlinformation so that timings of scheduling do not overlap, and therebycan cause the two communication services to coexist. When it isdetermined that there is a combination of radio access techniques thatcan coexist, the control unit 140 recommends use of the radio accesstechniques and a common channel (step S162). On the other hand, whenthere is no combination of radio access techniques that can coexist, theprocess proceeds to step S163.

In step S163, the control unit 140 determines whether or not it ispossible to assign different channels to the two second communicationservices (step S163). Here, when it is possible to assign differentchannels to the two second communication services, the control unit 140recommends that the secondary usage nodes 20 a and 20 b use thedifferent channels (step S164). For example, when permissible channelinformation from the secondary usage nodes 20 a and 20 b include thechannels F1 and F2 in common, the channel F1 can be recommended to thesecondary usage node 20 a, and the channel F2 can be recommended to thesecondary usage node 20 b. On the other hand, when it is not possible toassign different channels to the two second communication services, theprocess proceeds to step S165.

In step S165, the control unit 140 determines whether or not sharing ofcommunication resources becomes possible by supporting sharing of thecommunication resources of the two second communication services (stepS165). For example, when it is possible to cause the two communicationservices to coexist in a time division method by supplying asynchronization signal to the secondary usage nodes 20 a and 20 b, itcan be determined that sharing of the communication. resources ispossible. In this case, the process proceeds to step S167. On the otherhand, when it is determined that sharing of the communication resourcesis not possible, the process proceeds to step S166. In step S166, sinceno recommendable combination is found, the control unit 140 notifies thesecondary usage node 20 a that no recommendable combination is found.

When the process proceeds to step S167, the location relationshipbetween the service areas of the two secondary communication servicesbelongs to class A or class B. Also, the communication resources can beshared. Such a combination of radio access techniques includes, forexample, a combination of OFDMA and CSMA. In this case, the control unit140 recommends use of different radio access techniques and a commonchannel (step S167). Subsequently, the control unit 140 causes exchangeof information that specifies a range of the shamble communicationresources between the secondary usage nodes 20 a and 20 b, and suppliesa synchronization signal to the secondary usage nodes 20 a and 20 b,thereby causing the two communication services that employ the differentradio access techniques to coexist.

When the process proceeds to step S170 of FIG. 10, the locationrelationship between the service areas of the two secondarycommunication services belongs to class C shown in FIG. 6. In this case,the control unit 140 determines whether or not a trigger for the ongoingprocess of determining a recommended service configuration is asecondary usage node (step S170). Here, when the trigger for the processof determining a recommended service configuration is a secondary usagenode, the process proceeds to step S172. On the other hand, when thetrigger for the process of determining a recommended serviceconfiguration is not a secondary usage node, the process proceeds tostep S171. In step S171, the control unit 140 determines whether or notmutual interference between the nodes of the two second communicationservices is an allowable level or less (step S171). For example, thecontrol unit 140 estimates an interference level between the two secondcommunication services on the basis of transmission powers of therespective second communication services and path loss according to thedistance between the nodes. At this time, a margin for absorbing anestimation error may be included in the estimation result of theinterference level. Also, the control unit 140 compares the estimatedinterference level with the allowable interference level according tonecessary communication quality (a minimum SINR and the like) of eachsecondary communication service. On the basis of the results, thecontrol unit 140 can determine whether or riot mutual interferencebetween the nodes is the allowable level. Alternatively, a node of asecond communication service may measure an actual interference level,and the communication control device 100 may receive the measurementresult for comparison with the allowable interference level. Also, anode of a second communication service may report a result of comparisonbetween an actual interference level and the allowable interferencelevel to the communication control device 100. Here, when the mutualinterference between the nodes of the two second communication servicesdoes not exceed the allowable level, the process proceeds to step S172.In step S172, the control unit 140 recommends that the secondary usagenodes 20 a and 20 b use a common channel irrespective of radio accesstechniques. On the other hand, when the mutual interference between thenodes of the two second communication services exceeds the allowablelevel, the process proceeds to step S173.

In step S173, the control unit 140 determines whether or not it ispossible to assign different channels to the two second communicationservices (step S173). Here, when it is possible to assign differentchannels to the two second communication services, the control unit 140recommends that the secondary usage nodes 20 a and 20 b use thedifferent channels (step S174). On the other hand, when it is notpossible to assign different channels to the two second communicationservices, the process proceeds to step S175

In step S175, the control unit 140 determines whether or not sharing ofcommunication resources becomes possible by supporting sharing of thecommunication resources of the two second communication services (stepS175). Here, when it is determined that sharing of the communicationresources is possible, the process proceeds to step S177. On the otherhand, when it is determined that sharing of the communication resourcesis not possible, the process proceeds to step S176. In step S176, sinceno recommendable combination is found, the control unit 140 notifies thesecondary usage node 20 a that no recommendable combination is found.

In step S177, the control unit 140 recommends use of different radioaccess techniques and a common channel (step S177). Subsequently, thecontrol unit 140 causes exchange of information that specifies a rangeof the shamble communication resources between the secondary usage nodes20 a and 20 b, and supplies a synchronization signal to the secondaryusage nodes 20 a and 20 b, thereby causing the two communicationservices to coexist by, for example, the time division method.

The flow of the process of determining a recommended serviceconfiguration by the communication control device 100 is not limited tothe example shown in FIG. 10A to FIG. 10C. In other words, some processsteps shown in FIG. 10A to FIG. 10C may be omitted or integrated, or anadditional step may be added. Also, the sequence of process steps may bechanged. Here, an example in which the communication control device 100adjusts a service configuration between two communication services hasbeen mainly described. However, this embodiment can also be applied tothe case of an adjustment among three or more communication services inthe same way.

When there are a normal channel and a restricted channel asrecommendable channels in steps S156, S162, S164, S167, S172, S174,S177, and the like shown in FIG. 10A to FIG. 10C, the normal channel canbe preferentially recommended. According to such a configuration, it ispossible to keep throughput of each second communication service highwhile increasing efficiency in frequency usage by an adjustment betweensecond communication services.

4. Typical Scenarios for Communication Control

The above-described adjustment between second communication services bythe communication control device 100 is useful for a variety ofscenarios. By way of example, five scenarios will be described below.

4-1. First Scenario

FIG. 11A and FIG. 11B are explanatory diagrams illustrating a firstscenario of a communication control process. Referring to FIG. 11A, theprimary usage node 10, the secondary usage nodes 20 a and 20 b, and thecommunication control device 100 are shown.

A frequency band including the channels F1, F2 and F3 is assigned to afirst communication service provided by the primary usage node 10. Amongthese channels, the primary usage node 10 is using the channel F1. Onthe other hand, the channels F2 and F3 are not being used.

The secondary usage node 20 a receives permission from a data server,which is not shown, and provides a second communication service on thechannel F2 using the radio access technique R1. Also, the secondaryusage node 20 b receives permission from the data server, which is notshown, and provides a second communication service on the channel F2using the radio access technique (RAT) R2. However, in this case, thedistance between the secondary usage nodes 20 a and 20 b is short, andthus a signal transmitted from, for example, the secondary usage node 20b causes interference with the secondary usage node 20 a. The secondaryusage node 20 a detects such interference, and reports that interferencehas occurred to the communication control device 100 (SIG1 a). Thisreport denotes a request for an adjustment between the secondcommunication services.

In this case, according to the process of determining a recommendedservice configuration exemplified in FIG. 10A to FIG. 10C, thecommunication control device 100 recommends a change in the channel thatis being used by, for example, the secondary usage node 20 a from F2 toF3 (SIG1 b). In this way; the secondary usage node 20 a can change thechannel for secondary usage with F3 to avoid interference and favorablycontinue secondary usage.

4-2. Second Scenario

FIG. 12A and FIG. 12B are explanatory diagrams illustrating a secondscenario of the communication control process. Referring to FIG. 12A,the primary usage node 10, the secondary usage nodes 20 a and 20 b, andthe communication control device 100 are shown again.

Like in the first scenario, even in this scenario, a frequency bandincluding the channels F2 and F3 is assigned to a first communicationservice provided by the primary usage node 10. Among these channels, theprimary usage node 10 is using the channel F1. On the other hand,particularly, the channel F2 is not being used.

The secondary usage node 20 a receives permission from a data server,which is not shown, and provides a second communication service on thechannel F2 using the radio access technique R1. However, the secondaryusage node 20 a can use the radio access technique R2 in addition to theradio access technique R1. Also, the secondary usage node 20 b receivespermission from the data server, which is not shown, and provides asecond communication service on the channel F2 using the radio accesstechnique R2. However, in this case, the distance between the secondaryusage nodes 20 a and 20 b is short, and thus a signal transmitted from,for example, the secondary usage node 20 b causes interference with thesecondary usage node 20 a. The secondary usage node 20 a detects suchinterference, and reports that interference has occurred to thecommunication control device 100 (SIG2 a).

In this case, according to the process of determining a recommendedservice configuration exemplified in FIG. 10A to FIG. 10C, thecommunication control device 100 recommends, for example, that thesecondary usage node 20 a switch the radio access technique from R1 toR2 (SIG2 b). In this way, the secondary usage node 20 a can form a meshnetwork using the same radio access technique R2 and the same channel F2as the secondary usage node 20 b to avoid interference and favorablycontinue secondary usage.

4-3. Third Scenario

FIG. 13A and FIG. 13B are explanatory diagrams illustrating a thirdscenario of the communication control process. Referring to FIG. 13A,the primary usage node 10, the secondary usage nodes 20 a and 20 b, andthe communication control device 100 are shown again.

Like in the previous scenarios, even in this scenario, a frequency bandincluding the channels F1, F2 and F3 is assigned to a firstcommunication service provided by the primary usage node 10. Among thesechannels, the primary usage node 10 is using the channel F1. On theother hand, the channels F2 and F3 are not being used.

The secondary usage node 20 a receives permission from a data server,which is not shown, and provides a second communication service on thechannel F2 using the radio access technique R2. Also, the secondaryusage node 20 b receives permission from the data server, which is notshown, and provides a second communication service on the channel F3using the radio access technique R1. Here, the secondary usage node 20 bcan use the radio access technique R2 in addition to the radio accesstechnique R1. In this case, the channels that are used by the secondaryusage nodes 20 a and 20 b are different, and thus large interferencedoes not occur between the two second communication services. However,for example, the terminal device 22 a that is located around thesecondary usage node 20 a and the terminal device 22 b that is locatedaround the secondary usage node 20 b belong to the differentcommunication services, and thus are not able to communicate with eachother. For this reason, the secondary usage node 20 a requests networkexpansion from the communication control device 100 according to thenecessity for communication between these terminal devices (SIG3 a).This request for network expansion denotes a request for an adjustmentbetween the second communication services.

In this case, according to the process of determining a recommendedservice configuration exemplified in FIG. 10A to FIG. 10C, thecommunication control device 100 recommends, for example, that thesecondary usage node 20 b switch the radio access technique from R1 toR2 and also use the channel F2 (SIG3 b). Also, the communication controldevice 100 supplies a synchronization signal (SYNC) for synchronizingthe secondary usage nodes 20 a and 20 b. In this way, the secondaryusage nodes 20 a and 20 b form a mesh network using the common radioaccess technique R2 and the common channel F2. As a result, thesecondary usage nodes 20 a and 20 b relay signals transmitted/receivedbetween the terminal devices 22 a and 22 b, and communication is enabledbetween the terminal devices 22 a and 22 b.

4-4. Fourth Scenario

FIG. 14A and FIG. 14B are explanatory diagrams illustrating a fourthscenario of the communication control process. Referring to FIG. 14A,the primary usage node 10, secondary usage nodes 20 a, 20 b and 20 c,and the communication control device 100 are shown.

Like in the previous scenarios, even in this scenario, a frequency bandincluding the channels F1, F2 and F3 is assigned to a firstcommunication service provided by the primary usage node 10. Among thesechannels, the primary usage node 10 is using the channel F1. On theother hand, the channels F2 and F3 are not being used.

The secondary usage node 20 b receives permission from a data server,which is not shown, and provides a second communication service on thechannel F2 using a radio access technique R3. Also, the secondary usagenode 20 c receives permission from the data server, which is not shown,and provides a second communication service on the channel F3 using theradio access technique R1.

Furthermore, in this scenario, the secondary usage node 20 a willreceive permission from the data server, which is not shown, and providea second communication service using the radio access technique R2.Permissible channel information allowed by the data server includes thechannels F2 and F3. However, even when the secondary usage node 20 auses any of the channels F2 and F3, it is not possible to start thesecond communication service due to interference caused by signals fromthe secondary usage nodes 20 b and 20 b located around it. For thisreason, the secondary usage node 20 a reports that interference hasoccurred to the communication control device 100 (SIG4 a).

In this case, according to the process of determining a recommendedservice configuration exemplified in FIG. 10A to FIG. 10C, thecommunication control device 100 recommends, for example, that thesecondary usage node 20 b use the channel F3 (SIG4 b). This is because alocation relationship between a service area A22 of the secondary usagenode 20 b and a service area A23 of the secondary usage node 20 ccorresponds to class C described above, and the secondary usage node 20c is using the channel F3. Also, the communication control device 100recommends, for example, that the secondary usage node 20 a use thechannel F2 (SIG4 c). In this way, the secondary usage rode 20 a canavoid interference and start secondary usage using the channel F2 thatis different from the channels used by the secondary usage nodes 20 band 20 c.

4-5. Fifth Scenario

FIG. 15A and FIG. 15B are explanatory diagrams illustrating a fifthscenario of the communication control process. Referring to FIG. 15A,the primary usage node 10, the secondary usage nodes 20 a and 20 b, andthe communication control device 100 are shown.

In this scenario, a frequency band including channels F1, F2, F3 and F4is assigned to a first communication service provided by the primaryusage node 10. Among these channels, the primary usage node 10 is usingthe channel F1. On the other hand, the channels F2, F3 and F4 are notbeing used.

The secondary usage node 20 a receives permission from a data server,which is not shown, and provides a second communication service on thechannel F3 using the radio access technique R1. Also, the secondaryusage node 20 b receives permission from the data server, which is notshown, and provides a second communication service on the channel F2using the radio access technique R2. In this case, the channels that areused by the secondary usage nodes 20 a and 20 b are different, and thuslarge interference does not occur between the two second communicationservices. Here, it is assumed that, in the second communication serviceprovided by, for example, the secondary usage node 20 a, needs of anapplication for, for example, a high data rate have been generated.Thus, in order to extend a band of the second communication service andimprove a data rate, the secondary usage node 20 a requests addition ofa channel from the communication control device 100 (SIG5 a). Thisrequest for addition of a channel denotes a request for an adjustmentbetween the second communication services.

In this case, according to the process of determining a recommendedservice configuration exemplified in FIG. 10A to FIG. 10C, thecommunication control device 100 recommends, for example, that thesecondary usage node 20 a use the channels F3 and F4 that are not beingused by the secondary usage node 20 b (SIG5 b). As a result, thesecondary usage node 20 a can provide the second communication servicein a wider hand than the previous band, that is, at a higher data ratethan the previous data rate, using the channels F3 and F4.

3. Summarization

Thus far, one embodiment of the present disclosure has been describedwith reference to FIG. 1 to FIG. 15B. In the above-described embodiment,the communication control device 100 recommends a radio access techniqueor a channel to be used to at least one secondary usage node on thebasis of a location relationship between service areas of two or moresecond communication services and radio access techniques that can beused by secondary usage nodes providing the second communicationservices. Accordingly, it is possible to adjust a configuration forsecondary usage between a plurality of second communication services. Inparticular, when a frequency band is secondarily used, there are manycases in which it is not found in advance what kind of radio accesstechnique each secondary usage node supports. Also, to give eachsecondary usage node a function for performing an adjustment betweensecond communication services is not practical in terms of cost, andmakes it difficult to ensure neutrality of the adjustment. Accordingly,provision of the neutral communication control device 100 that collectsinformation about each secondary usage node such as a radio accesstechnique, and the like and performs an adjustment between secondcommunication services is useful in terms of cost and also neutrality ofthe adjustment.

Also, in the above-described embodiment, the communication controldevice 100 selects a channel that is recommended to each secondary usagenode from among channels that are allowed for the secondary usage nodeto use. Accordingly, when the communication control device 100 performsan adjustment, there is no risk of interfering with a firstcommunication service or other communication services that can bemanaged around the corresponding secondary usage node.

Furthermore, in the above-described embodiment, when a secondary usagenode detects interference between second communication services, aconfiguration of the second communication services can be changed toavoid the interference. When the secondary usage node requests expansionof a service area, the configuration of the second communicationservices can be changed to expand the service area. When the secondaryusage node requests expansion of a band, the band of a secondcommunication service can be expanded without newly causinginterference. In this way, users' opportunities for secondary usageincrease, and efficiency in frequency usage improves.

In addition, a control process of the communication control device 100and the secondary usage nodes 20 described in this specification can beimplemented using software. Programs constituting the software thatimplements the aforementioned control process are contained in advanceon a storage medium installed in or outside each device. Each program isread, for example, by a Random Access Memory (RAM) upon execution andexecuted by a processor such as a Central Processing Unit (CPU) or thelike.

The preferred embodiments of the present invention have been describedabove with reference to the accompanying drawings, whilst the presentinvention is not limited to the above examples, of course. A personskilled in the art may find various alternations and modificationswithin the scope of the appended claims, and it should be understoodthat they will naturally come under the technical scope of the presentinvention.

REFERENCE SIGNS LIST

10 Primary usage node

20 Secondary usage node

40 Data server

100 Communication control device

110 Communication unit (communication control device)

120 Storage unit (communication control device)

130 Estimation unit (communication control device)

140 Control unit (communication control device)

210 First communication unit (secondary usage node)

220 Second communication unit (secondary usage node)

230 Storage unit (secondary usage node)

240 Secondary usage control unit (secondary usage node)

1. A communication control device which controls communication of one ormore secondary usage nodes providing second communication services usinga part of a frequency band assigned to a first communication service,the communication control device comprising: circuitry configured to:receive service area information for estimating service areas of thesecond communication services provided by the secondary usage nodes andaccess technique information indicating radio access techniques usableby the secondary usage nodes from the respective secondary usage nodes;store the service area information and the access technique information;estimate service areas of two or more second communication servicesusing the service area information; and notify a secondary usage nodeproviding at least one of the two or more second communication servicesof a radio access technique or a channel recommended to the at least onesecond communication service on the basis of a location relationshipbetween the estimated service areas of the two or more secondcommunication services and the access technique information, wherein theservice area information includes data about a location of a secondaryusage node providing the corresponding second communication service, anda maximum transmission power applied to the secondary usage node.
 2. Thecommunication control device according to claim 1, wherein the serviceinformation further includes an antenna height of the secondary usagenode.
 3. The communication control device according to claim 1, whereinthe circuitry is further configured to: receive permissible channelinformation indicating a channel that the secondary usage node isallowed to use from the secondary usage node; and select a channelrecommended to each secondary usage node from among channels indicatedby the permissible channel information received from the secondary usagenode.
 4. The communication control device according to claim 1 wherein,when service areas of two second communication services overlap andradio access techniques usable by two secondary usage nodes respectivelyproviding the two second communication services are the same, thecircuitry is configured to recommend use of the same radio accesstechnique.
 5. The communication control device according to claim 4,wherein, when one of the two second communication nodes is not includedin a service area of the other second communication service, thecircuitry is configured to transmit a synchronization signal to the twosecondary usage nodes.
 6. The communication control device according toclaim 1, wherein, when service areas of two second communicationservices overlap and radio access techniques usable by two secondaryusage nodes respectively providing the two second communication servicesare different, the circuitry is configured to recommend that a secondaryusage node providing one of the second communication services use achannel different from a channel used by the other second communicationservice.
 7. The communication control device according to claim 1,wherein, when service areas of two second communication services do notoverlap and a level of mutual interference between the two secondcommunication services does not exceed an allowable interference level,the circuitry is configured to recommend that two secondary usage nodesrespectively providing the two second communication services use acommon channel.
 8. The communication control device according to claim1, wherein, according to a request from a secondary usage node detectinginterference between second communication services, the circuitry isconfigured to notify the secondary usage node or another secondary usagenode whose service area overlaps a service area of the secondary usagenode of a recommended radio access technique or a recommended channel.9. The communication control device according to claim 1, wherein,according to a request from a secondary usage node requesting expansionof a service area, the circuitry is configured to notify the secondaryusage node or another secondary usage node capable of using the sameradio access technique as the secondary usage node of a recommendedradio access technique or a recommended channel.
 10. The communicationcontrol device according to claim 1, wherein, according to a requestfrom a secondary usage node requesting expansion of a band, thecircuitry is configured to notify the secondary usage node of arecommended channel.
 11. The communication control device according toclaim 1, wherein, when there are a plurality of recommendable channels,the circuitry is configured to preferentially recommend a channel whosetransmission power has no limitation.
 12. A communication control methodfor controlling communication of one or more secondary usage nodesproviding second communication services using a part of a frequency bandassigned to a first communication service, the communication controlmethod comprising: receiving service area information for estimatingservice areas of the second communication services provided by thesecondary usage nodes and access technique information indicating radioaccess techniques usable by the secondary usage nodes from therespective secondary usage nodes; storing the received service areainformation and access technique information; estimating service areasof two or more second communication services 15 using the service areainformation; and notifying a secondary usage node providing at least oneof the two or more second communication services of a radio accesstechnique or a channel recommended to the at least one secondcommunication service on the basis of a location relationship betweenthe estimated service areas and the access technique information,wherein the service area information includes data about a location of asecondary usage node providing the corresponding second communicationservice, and a maximum transmission power applied to the secondary usagenode.
 13. A communication system which includes one or more secondaryusage nodes providing second communication services using a part of afrequency band assigned to a first communication service and acommunication control device controlling communication of the one ormore secondary usage nodes, wherein the communication control deviceincludes: circuitry configured to: receive service area information forestimating service areas of the second communication services providedby the secondary usage nodes and access technique information indicatingradio access techniques usable by the secondary usage nodes from therespective secondary usage nodes; store the service area information andthe access technique information; estimate service areas of two or moresecond communication services using the service area information; notifya secondary usage node providing at least one of the two or more secondcommunication services of a radio access technique or a channelrecommended to the at least one second communication service on thebasis of a location relationship between the estimated service areas oftwo or more second communication services and the access techniqueinformation, and wherein each of the secondary usage nodes includescircuitry configured to: transmit the service area information and theaccess technique information to the communication control device; andprovide a second communication service to one or more terminal devicesusing the radio access technique or the channel recommended by thecommunication control device, wherein the service area informationincludes data about a location of a secondary usage node providing thecorresponding second communication service, and a maximum transmissionpower applied to the secondary usage node.
 14. A communication devicewhich provides a second communication service using a part of afrequency band assigned to a first communication service, thecommunication device comprising: circuitry configured to: transmitservice area information for estimating a service area of the secondcommunication service provided by the communication device and accesstechnique information indicating a radio access technique usable by thecommunication device, to another device; and provide the secondcommunication service to one or more terminal devices using a radioaccess technique or a channel recommended by the other device on thebasis of a location relationship between a service area of the secondcommunication service estimated using the service area information and aservice area of another second communication service and the accesstechnique information, wherein the service area information includesdata about a location of a secondary usage node providing thecorresponding second communication service, and a maximum transmissionpower applied to the secondary usage node.